High spin states in neutron-rich ~(106)Tc nucleus

The high spin states of the neutron-rich odd-odd 106Tc nucleus have been reinvestigated by observing prompt γ-rays from the spontaneous fission of 252Cf. A previously known collective band is confirmed and expanded, and a new collective band is newly identified. Several levels in previous report in 106Tc are reexamined and they belong to the members of a band in 107Tc. The total Routhian surface (TRS) calculations show that the 106Tc has triaxial shape. The spins and parities as well as the configurations f...     

双奇核136La的集体带结构

通过重离子核反应与在束γ谱的实验技术, 对A=130缺中子核区的双奇核¹³⁶La的高自旋态进行了研究, 所用核反应为¹³⁰Te(¹¹B,5n). 实验结果扩展了¹³⁶La的能级纲图, 包括3个集体转动带, 最高自旋态达20h. 对于\uppi h_{11/2}\otimes \upnu h_{11/2}$~带, 观测到了旋称反转与集体回弯现象. 通过系统学比较, 对旋称反转特性进行了讨论. 由推转壳模型的计算指出, 此集体回弯是由一对中子的角动量顺排引起的. 另外两个集体带为具有~$\gamma\approx -60^\circ$~的扁椭形变带, 其可能的组态为: $\uppi h_{11/2}\otimes \upnu g_{7/2}h_{11/2}^2$~与~$\uppi g_{7/2}\otimes\upnu g_{7/2}^2 d_{5/2} h_{11/2}^2$.     

146Ce核的八级形变带和准γ带

通过测量²⁵²Cf自发裂变所产生的瞬发γ射线, 对¹⁴⁶Ce核的高自旋结构进行了重新研究, 结果更新了以前报道的能级纲图, 把八级形变集体带扩展到更高的自旋, 并且重新构建了可能的准γ带结构. 此外, 用反射不对称壳模型(RASM)对¹⁴⁶Ce核的八级形变带进行了计算, 低自旋处的计算结果与实验数据符合得很好.     

Search for chiral bands in A~110 neutron-rich nuclei

High spin states in A~110 neutron-rich ¹⁰⁶Mo, ¹¹⁰Ru and ¹¹²Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of ²⁵²Cf. Two similar sets of bands are observed to high spins in each of three nuclei. Through analyzing of characters of the band structures, the chiral doublet bands are suggested in ¹⁰⁶Mo, ¹¹⁰Ru and ¹¹²Ru.     

High Spin Band Structure in ^112Ru

Levels in the neutron-rich ^112Ru nucleus have been investigated by observing prompt gamma-rays from the spontaneous fission of ^252Cf with the Gammasphere detector array. The ground state band and the one-phonon γ-vibrational band have been confirmed and extended with spin up to 16h and 15h, respectively. The other two side bands, one proposed as two-phonon γ-vibrational band and the other proposed as two-quasiparticle band, have been observed for the first time. The total-Routhian-surface calculations show that rotational 112 Ru nucleus has triaxial deformation with parameters β2 - 0.27 and γ= -29°. The observed band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons according to the cranked shell model calculations. The possible configuration for the quasiparticle band has also been discussed.     

A=130区缺中子核122Cs与134Ce高自旋态研究

通过重离子核反应与在束γ谱的实验技术,对A=130缺中子核区122Cs与134Ce核的高自旋态进行了研究,所用核反应分别为107Ag(19F,1p3n)与122Sn(16O,4n).实验结果扩展了122Cs与134Ce的能级纲图.在122Cs中发现可能是属于手征二重带的结构,而在134Ce核的高自旋态结构中呈现出重要的具有不同γ形变的形状共存特性.Through heavy ion nuclear reaction and in-beam γ-ray spectroscopy technique, the high spin states of neutron-deficient~(122)Cs and~(134)Ce nuclei in A=130 region have been studied. The~(107)Ag(~(19)F, 1p3n) and~(122)Sn(~(16)O, 4n) reactions were used. The previous level schemes of~(122)Cs and~(134)Ce have been extended. Possible chiral doublet bands in~(122)Cs have been observed and a shape coexistence with different γ values in~(134)Ce are suggested.     

A=130区核高自旋态及形状驱动效应

通过重离子核反应与在束γ谱的实验技术, 对A=130缺中子核区的¹³⁴Ce,¹³⁶La与¹²²Cs核的高自旋态进行了研究, 实验结果扩展了¹³⁴Ce,¹³⁶La与¹²²Cs的能级纲图. 由于在此区内质子与中子的形状驱动效应, 在这3个核中各自形成了具有显著特点的集体转动带: ¹³⁴Ce$核的高自旋态结构中呈现出具有不同γ形变的形状共存特性;在¹³⁶La中，扩展了πh_11/2⊙νh_11/2带, 对其特性进行了讨论, 并发现了两个γ≈－60°的扁椭形变带; 在¹²²Cs$中发现可能是属于手征二重带的结构. 而对于在最近国外报道的¹³⁴Ce$核中的磁转动带没有被我们的实验所证实.     

丰中子核108Ru的集体带结构

通过对重核²⁵²Cf自发裂变产生的瞬发γ谱的测量, 对丰中子核¹⁰⁸Ru的能级结构进行了研究. 基带、单声子γ振动带和一个二准粒子带分别得到了确认和扩展, 同时识别了一个新的边带, 初步认定为二声子γ振动带. TRS模型计算表明¹⁰⁸Ru核具有三轴形变，其形变参量为β₂～0.29, γ=－22°. 推转壳模型的计算结果表明¹⁰⁸Ru核基带回弯是由h_11/2轨道的一对中子发生角动量的顺排所致. 对二准粒子带的组态特性也进行了讨论.     

丰中子Ru奇A核能级结构的进一步研究

通过对重核2?52?Cf自发裂变产生的瞬发γ谱的高精度测量数据的分析,扩展了丰中子奇A核10?9,111Ru的高自旋态,对不同延迟符合矩阵的数据分析,得到了10?7,10?9,111,113Ru低激发态多个能级的寿命,发现10?9Ru核中的96?.4keV的能级为一寿命约为130?0ns的同质异能态.对10?9,111Ru转动带的转动惯量随转动频率变化的分析表明,在相邻偶偶核110?Ru中观测到的集体回弯现象确实起源于一对h11/?2?中子的角动量顺排.用粒子?转子模型对10?7,10?9,111,113Ru的集体带的部分能级及跃迁几率进行了计算,得到与实验较为满意的符合,指出在这几个核中的中子h11/?2?闯入带尼尔逊轨道的起源.     

134Ba核的高激发态能级结构研究

在中国原子能科学研究院H-13串列加速器上, 通过重离子核反应¹³⁰Te(⁹Be,5n)与在束γ谱的实验技术, 对A=130缺中子核区的¹³⁴Ba核的高自旋态进行了研究, 建立了¹³⁴Ba核的新的能级纲图, 最高自旋态扩展到20h. 除验证了以前报道的大部分能级与跃迁外, 将基带的能级扩展到10⁺, 同时发现了基于10⁺同质异能态以上的众多的能级与跃迁. 对实验结果的系统学分析表明, 10⁺同质异能态为yrast陷阱, 起源于两中子组态, 可能具有γ≈－120°的长椭形状, 在其以上的能级表现出很强的单粒子性，具有复杂的结构. 基带中观测到明显的集体回弯现象, 推转壳模型的计算表明, 此集体回弯是由一对中子的顺排所致, TRS计算表明, 随着转动频率的增加, 核的形状发生明显的变化, 基带中在中子顺排后核具有γ≈－60°的扁椭形状.